smoky yanmar; any ideas?

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snappy

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Was lucky enought to blag a trip in a friend's cruiser recently. She has twin 6 cyl Yanmars, turbocharged with very few hours on them but a distinct lack of recent use. Both were "fully serviced" in March this year but hardly used since. We had usual start up smoke from both and port engine cleared quickly, but even after prolonged blast at the end of our trip after continuous operation at various throttle settings, the stbd engine was still producing a white cloud of steamy-looking smoke. Both were revving ok, ticking over smoothly so not apparently down on revs or power, although I would imagine they were working hard as her bottom would have been pretty filthy. Owner thought a longer blast would clear it but I am not convinced. Any ideas on likely causes and cures?
 
snappy said:
Was lucky enought to blag a trip in a friend's cruiser recently. She has twin 6 cyl Yanmars, turbocharged with very few hours on them but a distinct lack of recent use. Both were "fully serviced" in March this year but hardly used since. We had usual start up smoke from both and port engine cleared quickly, but even after prolonged blast at the end of our trip after continuous operation at various throttle settings, the stbd engine was still producing a white cloud of steamy-looking smoke. Both were revving ok, ticking over smoothly so not apparently down on revs or power, although I would imagine they were working hard as her bottom would have been pretty filthy. Owner thought a longer blast would clear it but I am not convinced. Any ideas on likely causes and cures?
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intersting the engines are different - my yanmar in my last boat always produced a lot of white steam in the exhaust that I whought at first was smoke.
 
Hello - I have an old for 'D' series engine in my boat that produces loads of 'white smoke' when it is started and even when fully wharmed up still produces a bit!

A wise man asked me if it was acrid - in other words did it catch your breath if you inhaled it - and it doesent! You can breath it in quite normally.
He went on to tell me that the 'white smoke' was in fact unburnt vapourised diesel!

I'm not an engineer but hope this might help.
Good luck...
 
snappy said:
Was lucky enought to blag a trip in a friend's cruiser recently. She has twin 6 cyl Yanmars, turbocharged with very few hours on them but a distinct lack of recent use. Both were "fully serviced" in March this year but hardly used since. We had usual start up smoke from both and port engine cleared quickly, but even after prolonged blast at the end of our trip after continuous operation at various throttle settings, the stbd engine was still producing a white cloud of steamy-looking smoke. Both were revving ok, ticking over smoothly so not apparently down on revs or power, although I would imagine they were working hard as her bottom would have been pretty filthy. Owner thought a longer blast would clear it but I am not convinced. Any ideas on likely causes and cures?
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You will need to be far more explicit, power output would be a helpful guide.

Yanmar do a range of quite different 6 cylinder engines 6LP, 6LY2, 6LY3 6CX. Base motors all very different, they have some individual quirks dependant on model, regarding white smoke.

At the moment it is a little like being a one legged man at ass kicking party. Once we have some specific answers I can provide a proper trouble shooting road map.
 
Latestarter1 said:
You will need to be far more explicit, power output would be a helpful guide.

Yanmar do a range of quite different 6 cylinder engines 6LP, 6LY2, 6LY3 6CX. Base motors all very different, they have some individual quirks dependant on model, regarding white smoke.

At the moment it is a little like being a one legged man at ass kicking party. Once we have some specific answers I can provide a proper trouble shooting road map.
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Thanks Latestarter; sorry I don't have any detail on which engine model but believe they are nominally rated at 315hp if that helps. Re temperature I don't recall any marked variation between the two sets of guages. It has been suggested to me that it was as much steam as smoke, indicating an issue with the exhaust?

thanks again for all replies
 
Snappy,

That is real helpful, it will be little 6LP.

Just another few questions:

#1 Is the white smoke/steam a new chachteristic?
#2 How long has your friend owned the engines?
#3 Have aftercoolers ever been serviced?
#4 No mention of any loss in performance, need 100% confirmation of this.

Good luck
 
This was a problem with 310/315hp models, but it not an issue on the 250/260hp, 350hp or 440hp engines. The 310/315 were persisantly smokey at low revs and on startup due overcooling.
 
Yanmar 6LP 315 4 valve (Toyota base) does smoke on start up. Less smoke on lower ratings 2 Valve simply because they have a lower specific output for the same displacement. Whilst the pump looks like a Bosch rotary, does NOT have the same feature 'Kaltstartbeschleuniger device' i.e has no way of advancing injection timing when cold to reduce white smoke. Once warm engine runs real clean and sweet.

Newer Tier II LP is just a little more smoky on start up.

Yanmar 6LY2 420/440 (Yanmar base motor) smokes just the same if not worse than 6LP. However for CERTAIN markets incorporated a smoke reduction grid heater which does wonders improving cold start white smoke performance.

New Yanmar Tier II 6LY3 380/440/480 is a complete dog.
Half assed mechanical/electronics, I think did away with the grid heater (need to look at my notes). Start up smoke pretty much the same as 6LYA2 pump only has limited timing control not a proper 3D timing table as common rail motor. The LDA(Air Fuel Control) set up being electronically controlled is now a nausiea.

Yanmar service tool sets up the LDA response, hit the throttles and response is amazing, but at the expense of clouds of black smoke. Costs you a visit from service guy with laptop to change LDA setting, get it wrong i.e. not allowing for weed growth and it costs you another visit. Go too far and you will blunt performance.

The old LY2 420/440 (Never 440 by the way in the same way that 370 was actually 350) had zero competition for years. Cummins QSB and Volvo D6 are now light years ahead of Yanmar LY's.

Yanmar privately accept LY3 is a lemon and are currently benchmarking D6 and QSB as pert of development process of a Tier III LY4 which will have Denso common rail. Yanmar's own DIY injection pump on the LY3 is guessed to be over £4K, but they will keep that a secret until you actually own one, then you can give your engine serial # to get a quote/fright.

Just hope to hell that they do not go down the whacky three pot start up to reduce white smoke as they have done on the latest Yanmar common rail CX engines.
 
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Latestarter1 said:
Yanmar 6LP 315 4 valve (Toyota base) does smoke on start up. Less smoke on lower ratings 2 Valve simply because they have a lower specific output for the same displacement. Whilst the pump looks like a Bosch rotary, does NOT have the same feature 'Kaltstartbeschleuniger device' i.e has no way of advancing injection timing when cold to reduce white smoke. Once warm engine runs real clean and sweet.

Newer Tier II LP is just a little more smoky on start up.

Yanmar 6LY2 420/440 (Yanmar base motor) smokes just the same if not worse than 6LP. However for CERTAIN markets incorporated a smoke reduction grid heater which does wonders improving cold start white smoke performance.

New Yanmar Tier II 6LY3 380/440/480 is a complete dog.
Half assed mechanical/electronics, I think did away with the grid heater (need to look at my notes). Start up smoke pretty much the same as 6LYA2 pump only has limited timing control not a proper 3D timing table as common rail motor. The LDA(Air Fuel Control) set up being electronically controlled is now a nausiea.

Yanmar service tool sets up the LDA response, hit the throttles and response is amazing, but at the expense of clouds of black smoke. Costs you a visit from service guy with laptop to change LDA setting, get it wrong i.e. not allowing for weed growth and it costs you another visit. Go too far and you will blunt performance.

The old LY2 420/440 (Never 440 by the way in the same way that 370 was actually 350) had zero competition for years. Cummins QSB and Volvo D6 are now light years ahead of Yanmar LY's.

Yanmar privately accept LY3 is a lemon and are currently benchmarking D6 and QSB as pert of development process of a Tier III LY4 which will have Denso common rail. Yanmar's own DIY injection pump on the LY3 is guessed to be over £4K, but they will keep that a secret until you actually own one, then you can give your engine serial # to get a quote/fright.

Just hope to hell that they do not go down the whacky three pot start up to reduce white smoke as they have done on the latest Yanmar common rail CX engines.
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Once again another excellent post from you for me to digest next time im hung over a 6lp wondering why I do this for a living!!, plenty of pointers on the yanmar smoke issues.
 
250 hp Yanmar 6 cyl'

Latestarter1, you clearly know your Yanmars!
I have a pair of 250 HP 6 cylinder Yanmars in my Broom 38 from 2000. It has done 400 hrs in that time, although wholly coastal.
They too are smoky on start up (blue) and to a much lesser degree at slow speed cruising.
They reach maximum rpm comfortably and run as sweet as a nut. They consume no oil of note.
I am not asking for a diagnosis, but are there any areas I should explore to ensure the set up is correct?
Thanks.
 
oceanfroggie said:
This was a problem with 310/315hp models, but it not an issue on the 250/260hp, 350hp or 440hp engines. The 310/315 were persisantly smokey at low revs and on startup due overcooling.
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I ran two 6LP's in my boat for 18 months. Assolutely no smoke unless in the depths of winter, best engines I've ever owned in that respect!!
In fact the guy who recently bought my boat did so to use on the Thames and the lack of smoke was a deciding factor over those Volvo chimney's!! That and the imperceptible motion going from neutral into gear. No clonks like my old Kad 44's.....
That said the Yanmars always displayed traces of white steam in the cooler months but nothing in the warmer summertime.
 
volvopaul said:
Once again another excellent post from you for me to digest next time im hung over a 6lp wondering why I do this for a living!!, plenty of pointers on the yanmar smoke issues.
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Ahh but there is the difference, never ask me to actually FIX an engine. Grazed hands due to shocking component accessability by the time first time spanner ends up in the bilge I have lost all interest.

On the dyno I can get all round an engine without damaging myself. Just sit down in a comfy chair then give a poor unsuspecting motor some real pain!

Some of the most interesting meetings to chair were those between the poeple who designed the engines and the service guys, just involved wiping the blood off the walls afterwards.
 
Latestarter1 said:
Ahh but there is the difference, never ask me to actually FIX an engine. Grazed hands due to shocking component accessability by the time first time spanner ends up in the bilge I have lost all interest.

On the dyno I can get all round an engine without damaging myself. Just sit down in a comfy chair then give a poor unsuspecting motor some real pain!

Some of the most interesting meetings to chair were those between the poeple who designed the engines and the service guys, just involved wiping the blood off the walls afterwards.
Click to expand...

Yes your quite right id like to get my hands around there necks too!!, its time they came and swapped a week with me on some of the boats we have to work on.
 
Problem is designers focus on the little bits they work on, and rarely see an engine in a boat... that's why engines get bigger with more 'hang on' parts that are always put where you can't reach them...
This is because they never go wrong and Service people obviously don't need to fiddle with these brilliantly designed perfect parts...:D

p.s. Marketing people are a damn sight worse than designers.....now those guys you could string up...They want everything designed yesterday, in a space 3 inches square, producing more power than is sensible, and has more features than you will ever need....just so they can cover the garbage they promised to the customer. "Sure, we can do a 1 litre 1000hp engine that will fit in a matchbox and will have teleporting capabilities to hide your girlfriend when the mrs shows up..." At that point I nearly feel sorry for designers... but not quite...:D
 
White smoke is an indication of water, it could be in the combustion chambers in which case it would be obvious white smoke; or most likely if the engines have stood, moisture in the oil.
Engines need to run at the correct temperature for the oil to work correctly, too cool and it takes a long time for the heat (what there is) to dry the oil of moisture and stop running white smoke from the exhausts. One other possibility is the exhaust running too hot and turning the water into steam, this could be inadequate water running through the exhaust.
 
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